Kazumi Tokiwa stands as one of the double main protagonists in the series, operating as Alice Myojingawa's partner in the vigilante duo Feathers. At 12 years old, she possesses light violet hair and brown eyes, consistently depicted wearing a four-leaf clover hairpin symbolizing her childhood friendship with Alice.

Her primary ability, Toys, manifests as a bow and arrow forged from light. This power synergizes seamlessly with Alice's barrier-based Toys, amplifying their combat effectiveness. Beyond tactical collaboration, their partnership includes shared activities like ice cream outings and watching sunsets while holding hands on the beach, illustrated in official art. Additional official art shows Kazumi exhibiting nervous reactions to physical proximity, such as Alice holding her arm.

Inspired by the Milky Holmes detective agency's heroism, Kazumi co-founded Feathers as a vigilante unit, reflecting her proactive dedication to justice. She appears across franchise installments including the main *Futari wa Milky Holmes* series, *Tantei Kageki Milky Holmes TD*, and films/specials like *Tantei Opera Milky Holmes Movie: Gyakushuu no Milky Holmes*, *Tantei Opera Milky Holmes: Arsene Karei naru Yokubou*, and *Tantei Opera Milky Holmes: Psycho no Aisatsu*.